Fluid pressure control apparatus



June 20, 1950 STEVENS 2,512,043

FLUID PRESSURE CONTROL APPARATUS Filed May 26; 1948 IN V EN TOR.

Roy R. Stevens BY v ATT ORLZE Y Patented June 20, 1950 UNITED STATES PATENT OFFICE FLUID PRESSURE CONTROLAPPARATUS Roy R. Stevens, illorestHills Pa assignorto The Westinghouse Air Brake Company, Wilmerding, Pa., a corporation of Pennsylvania Application May 26, 1948, Serial No; 29,243

5 Claims. 1

This invention relates to control apparatusand more particularly to the fluid pressure type.

In. certain types of control systems dependent uponfluid under pressure for their operation it may be essential that supply of said fluid under pressure does not fail duringoperation, and the principal object. ofthe inventionis the provision of improved safety meansfor ensuring this re.-

sult.

According to this object, I, associate with a normal source of supply of fluid under pressure.

and a fluid pressure delivery pipe, a reserve or emergency reservoir for storing fluid under pressure. and meansv automatically operative to control charging of the emergency reservoir with fl'uid under pressure from the normal source and release of fluid under pressure. from said reservoir to the delivery pipe in case of failure of the normal source. I further provide audible signal means in the form of a whistle for indicating Description As shown in the drawing, the apparatus comprises a normal fluid pressure supply reservoir l adapted to be charged with fluid under pressure through a pipe 2 by operation of a, cornpressor S; Fluid under pressure is taken from reservoir through a fluid pressure supply pipe 5 to a fluid pressure delivery pipe fi, via a double check valve device 3, to furnish normal supply of fluid under pressure from reservoir l to any apparatus or controls utilizing fluid under pressure.

According to the invention, the apparatus further comprises a reserve or emergency reservoir la, two relay valve devices 8, 9 of identical structure, two chokes it, M, an audible signal device in the form of a Whistle l2 and a check valve device 4!.

The relay'valve devices 3, 9 each comprises a casing in which. is" clamped a diaphragm I4. I

At. one side of diaphragm it there is a control pressure'chamber !5. adapted to be supplied with fluid under pressure for urging saiddiaphragm to deflect in the direction of a chamber 5'5 at its oppositeside. Chamber le-i open-to atmos- 2 phere by way of a port I-|.,--in= the casing. A control spring i8 is disposed in chamber I6 adapted and arranged: to urge diaphragm I l in the directionof control chamber l5 toward its restposition. l9 formed in the;

in contact with a. shoulder casing, in which position it is shown in the drawing. A stem 28 is secured for reciprocable move-.-

ment withdeflection of diaphragm I4 for actuate ing valves 2|, 22.

ber l6 from a chamber 25.

valve 2| which is. disposed in the chamber 25.

By reciprocable movement of stem 20, valve 2-! is.

brought into andoutof seatin engagementwith a hollow cylindrical seat element 26 which is slidably mounted in a. bore 2'! extending through a partitionwhich separates the'chamber 25 froma chamber 29. Seatelement 2-6 extendsthrough the chamber 29 and through an opening 30 in:

a. partition separating said chamber from a chamber 3i. The,valve. 22 disposed in the chamber is attached. to the end of stem 26 andlarranged;

to cooperate with aseat formed at one end of. opening. 30 to. control communication there,- throughbetween said chamber and the chamber 29.

extends longitudinally through s eatl element 26, which when valve 2| is unseated, connects the chamber 25 to thechamber 3|. When valve 2! is seated opening33 is closed.

When fluid under pressure is supplied to, thev control chamber l5, through consequent defies-.- tion of diaphragm. l4 and thereby movement of stem 20, valve Zlis brought into seating engages ment with element 26 which isv then moved to unseat the attached valve 22. At this timechamr ber 25 is closed to chamber 3!. and the latter chamber is open to chamber 29.

When pressure of fluid is released from con:

trol chamber l5, the relay valve devices will.

again assume their position in which they are shown in the drawing with valve 22 seated and valve 2-! unseated. At this time chamber 251's open to chamber 3| and the latter chamber is closedto chamber 29.

In relay valve device 8, the control chamber 35 is also connected, to control chamber l5 oft relay valve device 9; Chamber 29 is connected to the; pipe 5;vi a a; pipe 5 andthereby tothe-cor-l.

Stem 2!] projects through. chamber I6 and is slidably guided me bore open-.- ing through a partition 24: which divides chame- The projecting: end; of stem 20 has an operating" connection with;

Av bias spring 32 is arranged to urge valve 2;. to a. seated position, A, central opening 3.3.

responding chamber 29 in relay valve device 3, and chamber Si is connected by way of a pipe 33 to the emergency reservoir la.

In relay valve device 9, chamber 25 is connected via a pipe 31 to atmosphere and chamber 3| is connected by way of a pipe 38 to the whistle l2.

Choke I is inserted in the pipe and the choke II, which offers more resistance to flow than does the choke ID, is inserted in a pipe 40 connecting pipe 35 with the pipe 38.

The check valve 41 is inserted in the communi-- cation between the normal supply pipe 5 and the emergency reservoir la to permit flow of fluid under pressure from the former to the latter but to prevent flow in the reverse direction. The check valve 41! is shown disposed in the pipe 5 between the valve device 8 and the normal supply pipe 5 to accomplish the intended purpose.

Operation In operation, assume initially that the whole apparatus is at atmospheric pressure, under which condition the diaphragms M in rela valve devices 8, 3 will be seated on the respective shoulders l9, and in both devices valve 22 will be seated and valve 2! unseated. Communication between supply pipe 5 via choke I0 and pipe 5', and the pipes 35 and 38, through the relay valve device 8 and 9, respectively, will be closed. Communication between pipes 35, 36 through valve device 8 will be open, and communication between the pipes 31, 38 through the valve device 9 will be open.

If now the compressor 3 is operated to efiect supply of fluid under pressure to the normal supply reservoir I, fluid under pressure will flow therefrom through the pipe 5 and the double check valve 1 to the delivery pipe 6, available for use.

Fluid under pressure supplied to pipe 5 at the same time will also flow into the control chamber l5 of the relay valve device 8 which will respond to establish communication therethrough between the pipes 5 and 36, whereupon fluid under pres-. sure from supply pipe 5 will flow through choke 10, pipe 5', check valve 4|, relay valve device 8 and pipe 36 to the emergency reservoir 1a which is thereby charged with fluid at a pressure which will increase substantially with that obtained in the normal supply reservoir. With sufficient lapse of time said pressure in the emergenc reservoir will reach the maximum pressure attainable in the normal supply reservoir l and will be prevented from subsequent reduction with reduction in pressure in said reservoir 1 by action of the check valve 4! which will prevent such reduction from occurring.

During this time pipe 38 connected. to the whistle 12 "will remain connected to the atmosphere via communication through relay valve device 9 and the pipe 37.

If fluid under pressure is now used from the delivery pipe 6, the pressure of fluid in the pipe 5 will tend to reduce, but normally will be maintained or restored by flow of fluid under pressure from the normal supply reservoir l and compressor 3.

However, if, due to excessive use of fluid under pressure from pipe 5 and reservoir I, or due to failure of compressor 3, or due to excessive leakage cf fluid under pressure from the normal supply source, the pressure in pipe 5 should become reduced below a certain minimum pressure considered to be adequate for supply to delivery pipe 6, such reduced pressure, in control chamber IS in relay valve device 3 will allow spring 18 to actuate diaphragm i l to open valve 2| and close valve 22 and thereby establish communication between pipe 35, connected to the emergency reservoir, and the pipe 35, connected to the double check valve device 1, and to disestablish communication between the pipe 5', connected to pipe 5, and the pipe 36.

Fluid under pressure from the emergency reservoir M will then flow through pipe 36, relay valve device 8, pipe 35, and through the double check valve device 1 into the delivery pipe 6 to assure adequate supply thereto and thereby prevent its undesired reduction with the accidental reduction in pressure of fluid in the normal supply reservoir l.

Fluid under pressure thus supplied to pipe 35 will at the same time flow to the control chamber l5 in the relay valve device 9 and, due to choke II, will cause sumcient pressure to promptly develop in said chamber to actuate said device to establish communication between pipes 5' and 3B and to disestablish communication between said pipe 38 and the pipe 31.

Fluid under pressure thus supplied to the pipe 38 flows to the whistle 2 for sounding same. The sound of the whistle l2 afiords an audible signal which warns an operator of apparatus utilizing fluid under pressure from the delivery pipe 6 that supply of fluid under pressure from the normal supply reservoir I has failed and that the emergency supply has been cut in, thus enabling said operator to employ the emergenc supply with discretion until normal supply is restored. It will be appreciated that such audible signal is operated automatically and at the same time that the emergency reservoir la is connected via pipe 35 to the delivery pipe 6.

When fluid in the normal supply reservoir 1 is reestablished at or above the aforementioned tolerable minimum pressure, such pressure in the control chamber i5 in the relay valve device 8 will cause same to again disestablish communication between pipes 35, 33 and to establish communication between the latter of these pipes and the pipe 5' for cutting on supply of fluid under pressure from the emergency reservoir 1a to delivery pipe 6 and for recharging said reservoir with fluid under pressure from the supply pipe 5. Pressure of fluid in the control chamber i5 in the relay valve device 9 will then leak off through pipe 35, pipe 49 via the small choke H, the pipe 38 and the whistle l2. When pressure of fluid in chamber [5 in valve device 9 is thus reduced sufficiently, said device will respond to disestablish communication between pipes 5' and 3B and to establish communication between the latter pipe and the pipe 31 to the atmosphere. The whistle I2 then stops sounding, in absence of supply of fluid under pressure thereto from the Pipe 5.

Summary It will be seen now that I have provided improved fluid pressure control apparatus automatically operative for assuring adequate supply of fluid under pressure to a fluid pressure delivery pipe in event that supply of fluid under pressure to said pipe from a normal fluid pressure source fails. I further provide improved means operative automatically to effect an audible signal for warning an operator that such condition exists.

Having now described my invention, what I claim as new and desire to secure by Letters Patent, is:

.1. In a control apparatus, the combination with a fluid pressure supply pipe, a fluid pressure reservoir, a fluid pressure delivery pipe, a first fluid pressure communication between said fluid pressure supply pipe and said fluid pressure delivery pipe, a second fluid pressure communication between said supply pipe and said reservoir and a third fluid pressure communication between said reservoir and said delivery pipe, of a relay valve device operable by pressure of fluid in said supply pipe at or above a chosen value to close said third fluid pressure communication and to open said second fluid pressure communication and operable upon a reduction in said pressure below said chosen value to close said second fluid pressure communication and to open said third fluid pressure communication, and double check valve means operable to disestablish connection between either of the first and third fluid pressure communications and said delivery pipe upon preponderance in pressure of fluid in the other of said communication.

2. In a control apparatus, the combination with a fluid pressure supply pipe, a fluid pressure reservoir, a fluid pressure delivery pipe, a first fluid pressure communication between said fluid pressure supply pipe and said fluid pressure delivery pipe, a second fluid pressure communication between said supply pipe and said reservoir and a third fluid pressure communication between said reservoir and said delivery pipe, of a relay valve device operable by pressure of fluid in said supply pipe at or above a chosen value to close said third fluid pressure communication and to open said second fluid pressure communication and operable upon a reduction in said pressure below said chosen value to close said second fluid pressure communication and to open said third fluid pressure communication, double check valve means operable to disestablish connection between either of the first and third fluid pressure communications and said delivery pipe upon preponderance in pressure of fluid in the other of said communications, and choke means disposed in said second fluid pressure communication.

3. In a control apparatus, the combination with a fluid pressure supply pipe, a fluid pressure reservoir, a fluid pressure delivery pipe, a first fluid pressure communication between said fluid pressure supply pipe and said fluid pressure delivery pipe, a second fluid pressure communication between said supply pipe and said reservoir and a third fluid pressure communication between said reservoir and said delivery pipe, of a relay valve device operable by pressure of fluid in said supply pipe at or above a chosen value to close said third fluid pressure communication and to open said second fluid pressure communication and operable upon a reduction in said pressure below said chosen value to close said second fluid pressure communication and to open said third fluid pressure communication, double check valve means operable to disestablish connection between either of the first and third fluid pressure communications and said delivery pipe upon preponderance in pressure of fluid in the other of said communications, a fluid pressure conduit, second relay valve means operable by pressure of fluid supplied to said third fluid pressure communication to effect supply of fluid under pressure from said supply pipe to said conduit, and fluid pressure operable signal means connected to said conduit.

4. In a control apparatus, the combination with a fluid pressure supply pipe, a fluid pressure reservoir, a fluid pressure delivery pipe, a first fluid pressure communication between said fluid pressure supply pipe and said fluid pressure delivery pipe, a second fluid pressure communication between said supply pipe and said reservoir and a third fluid pressure communication beween said reservoir and said delivery pipe, of a relay valve device operable by pressure of fluid in said supply pipe at or above a chosen Value to close said third pressure communication and to open said second fluid pressure communication and operable upon a reduction in said pressure below said chosen value to close said second fluid pressure communication and to open said third fluid pressure communication, double check valve means operable to disestablish connection between either of the first and third fluid pressure communications and said delivery pipe upon preponderance in pressure of fluid in the other of said communications, a fluid pressure conduit, second relay valve means operable by pressure of fluid supplied to said third fluid pressure communication to effect supply of fluid under pressure from said supply pipe to said conduit, fluid pressure operable signal means connected to said conduit, and choke means connecting said conduit with said third fluid pressure communication.

5. In a control apparatus, the combination with a fluid pressure supply pipe, a fluid pressure reservoir, a fluid pressure delivery pipe, a first fluid pressure communication between said fluid pressure supply pipe and said fluid pressure delivery pipe, a second fluid pressure communication between said supply pipe and said reservoir and a third fluid pressure communication between said reservoir and said delivery pipe, of a relay valve device operable by pressure of fluid in said supply pipe at or above a chosen value to close said third fluid pressure communication and to open said second fluid pressure communication and operable upon a reduction in said pressure below said chosen value to close said second fluid pressure communication and to open said third fluid pressure communication, double check valve means operable to disestablish connection between either of the first and third fluid pressure communications and said delivery pipe upon proponderance in pressure of fluid in the other of said communications, choke means disposed in said second fluid pressure communication, a fluid pressure conduit, second relay valve means operable by pressure of fluid supplied to said third fluid pressure communication to effect supply of fluid under pressure from said supply pipe to said conduit, fluid pressure operable signal means connected to said conduit, and second choke means connecting said conduit with said third fluid pressure communication, said second choke means being of lesser capacity than the first-named choke means.

ROY R. STEVENS.

REFERENCES CITED The following references are of record in th file of this patent:

UNITED STATES PA'I'ENTS Number Name Date 1,469,585 McCune Oct. 2, 1923 2,379,308 McClure June 26, 1945 

